A stronger ACL needs to be on the secrets file

[DanaEpp]

Issue

Bruno currently stores its Secrets variables in /Users/{username}/Library/Application Support/bruno/secrets.json on macOS. By default, this file has permissions set with world READ and WRITE privileges. (666 perms).

Similar to issue #2016, I think this could have a more secure default of 600.

An argument could be made that the bruno directory is already locked down with 700 perms; however, backups and archival that honor the perms could carry this permission outside of that directory and ultimately expose the secrets. Even though they are encrypted, the principle of least privilege should apply here, and the permissions should be changed to reduce the attack surface of the secrets file. Otherwise, what's its purpose? You may as well put the encrypted values in the normal Environment .bru files.